Cementing heads are well known in the field of petroleum exploration, well completion, production and abandonment. A cementing job is typically performed for pumping wet cement down a well to fill the space between the casing and the formation and for closing a well path. In this operation a cementing head is the connection between the cement pump and the cement line in the well, and is used for controlling valves located in the flow line of cement, said valves control the release of wiper plugs separating cement flow from fluids in front of and back of it.
Applicants' own publication WO-2008/082307 with the title “Pressure driven apparatus for sequential control of a cement head” show related art.
Operation of a cement head is described, and FIG. 2A in said WO-publication shows a control panel with direct pneumatic control of valves on the cement head by using pressurized gas. This is achieved with a control line comprising an air hose connected between the control panel and the cement head.
The pneumatic remote control thus removes the need to operate the valves manually, but still requires personal to be present in the red zone on drill floor. FIG. 1 in the accompanying figures in the disclosure shows the set-up with said pneumatic remote control.
The QHSE (Quality, Health, Safety & Environment) policy of most rig operators is to reduce the number of persons in the red zone as much as possible. The pneumatic remote control also depends on use of a swivel. This is a mayor drawback as the swivel reduce permitted rpm rate. During liner cementing operation, rotation rate sometimes exceeds the permitted rate. If the swivel fails, the connection between the cement head and, the control line can represent a risk. With hoses connecting the control panel to the cement head, the risk of equipment being damaged during operation increases since hoses often are not properly protected from the environment and activities on drill floor.
There is therefore a need for operating a cement head without exposing personnel to risk.
The present invention suggests removing the control line and applying wireless controlled means instead. This will result in several technical advantages and reduced risk to personnel. The need to have personal in the red zone will be reduced, thereby reducing risk to personnel due to falling objects. It will also remove problems with swivel on liner jobs. The same cement head can also be used on both liner and casing cementing jobs.
A wireless controlled cement head presents several technical challenges to be solved. One of these is how to provide sufficient energy for operating valves used for releasing wiper plugs.
This and other aspects are solved in the present invention as described in the detailed description.